安徽休宁陡山沱期后生植物化石的新认识

A NEW DEA OF METAPHYTE FOSSILS FROM THE LATE SINIAN DOUSHANTUO STAGE AT XIUNING, ANHUI PROVINCE

本文对中国安徽省休宁地区震旦纪陡山沱期蓝田组的化石资料进行了综述,报道了类似现代某些高等藻类的生殖托化石结构和类似孢子囊裂开的化石结构,以及可能是合子萌发成胚,再发育成底栖固着的藻类成体的个体发育现象,这一现象为进一步探讨高等藻类世代交替的生活历史提供了有益的线索,是后生藻类植物性别分化的宏观化石证据。

The carbonaceous shale of the Late Sinian Doushantuo Stage of the Lantian Formation in Xi-uning area. Anhui Province. Southern China, contains an exceptionally well-preserved carbonaceous megafossil assembleage of Metaphyta called the 'Lantian Flora', which is the product of the first radiation of Metaphyta in the earth history. Xing Yusheng (1984.1985,1989). Bi Zhiguo et al. (1987) .Yan Yongkui et al. (1992). Chen Menge et al. (1994) outlined the Neo-proterozoic macro-algal fossils, which are represented by disc-, spindle-. cup-. fan- or clump-shaped carbonaceous thalli. And the new fossils evidence supports the authors' analysis which as follow: (1) The disc-shaped films,generally called 'Chuarids',can be of different origins. After the glacial epoch, many Chuarids with coccoid habit emerged. (2) The spindle-shaped algal fossils were first found in 1984 and described in 1992. Morphologically compared with modern algae . they are very similar in outline to the genital butt of Fucus L. , with the sporophyte comparable to a kind of branched algae fossil Enteromophites siniansis Zhu et Chen (1984) from the Doushantuo Formation at Miaohe. Hubei Province. (3) The cup-, fan- and clump shaped carbonaceous thalli might be preserved in different growth stages of the rhodophyte filaments. The cup-shaped fossils consist of filaments like rafts which are fused laterally, and are crowded closely in a thin membrane. The filaments branched constantly during their growth and the thalli broadened and became a fan-shaped outline. When the metaphyta matured into-propagating alga which might give rise to a lot of free spores with connection to the Chuarids, the filaments bursted and drifted freely to show a clump-shaped feature.